"And for their sakes I sanctify myself, that they also might be sanctified through the truth." (John 17:19)
In "Biblical Perspective" Randall McElwain writes:
It is God's Word, the truth, that provides the power by which the disciples would be transformed (Beacon Bible Comm.). It is God's Son and His self-consecration that makes sanctification possible. While we correctly associate the Holy Spirit with sanctification, it is a trinitarian doctrine; all members of the Trinity play a role in our sanctification. When Jesus prayed for their sakes I sanctify myself, He used the same language used in New Testament atonement passages. Examples include Mark 14:24 (“this is my blood of the new testament, which is shed for many”) and John 6:51 (“and the bread that I will give is my flesh, which I will give for the life of the world”). Just as Jesus provided for our atonement, He provided for our sanctification.
Source: Jesus, Son of God: Adult Teacher's Insights, page 67.